Symptoms and Treatment of Frey's Syndrome
Frey's syndrome is characterized by sweating, flushing, and warming over the preauricular and temporal areas following a gustatory stimulus, and is most effectively treated with intradermal botulinum toxin injections or topical glycopyrrolate application.
Symptoms
Frey's syndrome presents with a characteristic triad of symptoms that occur during eating or in response to salivary stimulation:
Primary symptoms:
- Sweating (gustatory sweating) in the preauricular and temporal areas
- Flushing of the skin in the affected area
- Warming sensation over the parotid region
Additional clinical manifestations:
- Symptoms typically occur unilaterally
- Symptoms are triggered by eating or salivary stimulation
- The affected area corresponds to the distribution of the auriculotemporal nerve
- Social embarrassment and psychological distress are common 1
Etiology
Frey's syndrome most commonly occurs following:
- Parotidectomy (most common cause)
- Submandibular gland surgery
- Radical neck dissection
- Infection in the parotid region
- Traumatic injury to the parotid area
- Temporomandibular joint surgery
- Herpes zoster infection (rare) 2
The underlying pathophysiology involves aberrant regeneration of parasympathetic nerve fibers that previously innervated the parotid gland. These fibers inappropriately connect with sympathetic fibers supplying sweat glands and blood vessels in the skin, causing sweating and flushing when salivation is stimulated 1, 3.
Diagnosis
Diagnosis is primarily clinical but can be confirmed with objective testing:
Minor's starch-iodine test: The gold standard diagnostic test
- Iodine solution is applied to the affected area
- Starch powder is sprinkled over the area
- Patient is given a gustatory stimulus (lemon juice or sour candy)
- A color change from white to dark blue/black indicates a positive test 2
Other diagnostic methods:
- Iodine-sublimated paper histogram method
- Blotting paper technique 1
Treatment Options
1. Topical Anticholinergics
Glycopyrrolate (1% solution, cream, or roll-on lotion)
Scopolamine (solution or cream)
- Alternative topical anticholinergic option
- May have more side effects than glycopyrrolate 4
2. Botulinum Toxin Injection
- Botulinum toxin type A
- Most effective treatment with high success rates
- Administered via intradermal injection (2 units per cm² of affected skin)
- Effects appear within 4-7 days
- Duration of effect: 7-10 months on average
- Minimal side effects 3
- Recommended for moderate to severe cases or when topical treatments fail
3. Surgical Interventions
Interpositional barriers during initial parotid surgery
- Preventive measure using materials like oxidized regenerated cellulose (Interceed)
- May reduce incidence of Frey's syndrome development 5
Other surgical options for refractory cases:
- Tympanic neurectomy
- Resection of the affected skin
- These are rarely used due to the effectiveness of less invasive options
Treatment Algorithm
Mild symptoms with minimal social impact:
- Topical glycopyrrolate 1% (roll-on lotion or cream)
- Apply before meals or social situations
Moderate to severe symptoms or failure of topical treatment:
- Intradermal botulinum toxin type A (2 units/cm² of affected area)
- Repeat every 7-10 months as needed
Refractory cases:
- Consider combination therapy
- Surgical consultation for severe cases unresponsive to other treatments
Important Considerations
- Early recognition and treatment are essential to prevent negative psychological and social impacts
- The condition is benign but can significantly affect quality of life
- Treatment should be initiated promptly when symptoms are confirmed
- Preventive measures during initial parotid surgery may reduce incidence
- Long-term management may be necessary as the condition is often chronic
Frey's syndrome, while not life-threatening, can significantly impact quality of life. Fortunately, effective treatments are available, with botulinum toxin injections and topical glycopyrrolate showing the best results for symptom control.